Carbon isotope chemostratigraphy and precise dating of middle Frasnian (lower Upper Devonian) Alamo Breccia, Nevada, USA

2009 ◽  
Vol 282 (1-4) ◽  
pp. 105-118 ◽  
Author(s):  
J.R. Morrow ◽  
C.A. Sandberg ◽  
K. Malkowski ◽  
M.M. Joachimski
Keyword(s):  
Carbon Isotope ◽  
Upper Devonian ◽  
Lower Upper

Review of the Devonian camerate crinoid Bogotacrinus scheibei Schmidt from Colombia

1987 ◽  
Vol 61 (4) ◽  
pp. 750-757 ◽  
Author(s):  
George C. Mcintosh
Keyword(s):  
North America ◽  
Western Europe ◽  
Lower Devonian ◽  
Appalachian Basin ◽  
Upper Devonian ◽  
Eastern North America ◽  
Late Devonian ◽  
Early Devonian ◽  
Lower Upper

Two recently collected specimens of Bogotacrinus scheibei Schmidt, 1937, from the Devonian (Emsian–Eifelian) Floresta Formation of Colombia reveal that Bogotacrinus is a dicyclic camerate crinoid genus closely related to Pterinocrinus Goldring, 1923 (Lower–Upper Devonian of eastern North America and western Europe), and Ampurocrinus McIntosh, 1981 (Lower Devonian of Bolivia). The new diplobathrid camerate crinoid family Pterinocrinidae, characterized by species with low conical dicyclic cups and rami composed of compound, bipinnulate brachials, is herein proposed to accommodate these three genera. This family originated in western Europe and migrated into the Malvinokaffric and southern Eastern Americas Realms during the Early Devonian and into the northeastern Appalachian Basin by the Late Devonian.

C isotopic variations in the lower–middle Frasnian (lower Upper Devonian) of the Rudny Altai

2015 ◽  
Vol 152 (3) ◽  
pp. 565-571 ◽  
Author(s):  
OLGA P. IZOKH ◽  
NADEZHDA G. IZOKH ◽  
STANISLAV V. SARAEV ◽  
GALINA A. DOKUKINA
Keyword(s):  
Carbon Isotope ◽  
Upper Devonian ◽  
Reef Facies ◽  
Fore Reef ◽  
Conodont Biofacies ◽  
Anoxic Event ◽  
Frasnian Stage ◽  
Geochemical Studies ◽  
Isotopic Variations ◽  
Isotope Analyses

AbstractWe conducted isotope–geochemical studies of the Upper Devonian of the Rudny Altai. Whole-rock carbon isotope analyses of the studied section represented by carbonate fore-reef facies reveal a negative excursion at the base of punctata Zone. When compared to conodont biofacies turnovers and the Upper Devonian events chart, the new data have demonstrated a synchronism between the negative excursion and the coeval decline in conodont biodiversity corresponding to the Middlesex anoxic event of the Frasnian Stage of the Upper Devonian.

Contribution a l'etude du Couvinien dans le bassin de Fort-de-Polignac (Sahara)

1961 ◽  
Vol S7-III (5) ◽  
pp. 449-456 ◽  
Author(s):  
Jean Chaumeau ◽  
Philippe Legrand ◽  
Alzine Renaud
Keyword(s):  
Middle Devonian ◽  
Lower Devonian ◽  
Upper Devonian ◽  
Lower Upper ◽  
Shaly Sandstone ◽  
Lateral Variations

Abstract The contact of lower Devonian sandstone and shaly sandstone with middle Devonian shaly limestone is exposed at several points in the vicinity of Fort-de-Polignac in the Sahara. The lower Devonian beds show large lateral variations. Instead of the Givetian (upper middle Devonian) transgressing the lower Devonian, as previously supposed, the transgression began in the center of the basin in the Couvinian or Eifelian, i.e., lower middle Devonian, spread progressively eastward and westward, and did not reach the Oued Samene area until upper Couvinian. The submergence of the lower part of Tihemboka, west of In Akaouet, did not occur until Frasnian (lower upper Devonian).

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